package chapter10.Example1;

import  java.sql.*;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.Statement;

public class Example1 {
    public static void main(String[] args) throws SQLException{
        /** JDBC连接数据库
         * 1.加载 驱动
         * 2.连接
         * 3.表结构
         * 4.预处理(SQL)
         * 5.结果
         * 6.释放 连接
         */
        /**
         * (1) 加载
         * a. 根目录创建lib文件夹
         * b. 将 连接的jar包放入lib
         * c. 点击 文件->项目结构->模块->依赖->+号->JAR或目录->选中mysql的jar包
         * d. 编写加载代码
         */
        Statement stmt = null;
        ResultSet rs =  null;
        Connection conn = null;
        try {
            // 1.注册数据库的驱动
            Class.forName("com.mysql.cj.jdbc.Driver");
            // 2.通过DriverManager获取数据库连接
            String url = "jdbc:mysql://localhost:3306/jdbc?serverTimezone=GMT%2BB&useSSL=false";
            String username = "root";//数据库账户
            String password = "123456";
            conn = DriverManager.getConnection(url, username, password);
            //3.通过Connection对象获取Statement对象
            stmt = conn.createStatement();
            //4.使用Statement执行SQL语句。
            String sql = "select * from users";
            rs = stmt.executeQuery(sql);
            //5.操作ResultSet结果集
            System.out.println("id | name | password | email | birthday");
            while (rs.next()) {
                int id = rs.getInt("id");
                String name = rs.getString("name");
                String psw = rs.getString("password");
                String email = rs.getString("email");
                Date birthday = rs.getDate("birthday");
                System.out.println("id + | + name + | + psw + | + email + | + birthday");
            }
        } catch(ClassNotFoundException e){
            e.printStackTrace();
        } finally {
            //6.回收数据库资源
            if(rs != null) {
                try {
                    rs.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
                rs = null;
            }
            if(stmt != null) {
                try {
                    stmt.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
                stmt = null;
            }
            if(conn != null) {
                try {
                    conn.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
                conn = null;
            }
        }
    }
}
